mathematical model development of regenerative thermal oxidizer for volatile organic compounds

I am trying to develop a regenerative thermal oxidizer for volatile organic compounds(VOCs) mathematical model using simscape gas elements.

I am facing problem with finding a appropriate sensor to detect whether the actual oxidation of VOCs is happening or not .

Is there any possible sensor available in simulink which can solve my purpose?

Answer 1

[Joel Van Sickel]

Hello Omkar,

the gas elements are for modelling the dynamics of a gas system, not it's chemical reactions. This particular domain also does not support multiple species. While you could model the gas dynamics of this system, you would not be modelling the oxidation process using the simscape gas library. You would need to develope your own reaction models for the oxidation process.

An alternative, would be to start with the moist air domain, only instead of moisture in the air, treat that as VOC's. This would require a decent amount of homework to understand building your own domain in simscape, but is doable.

https://www.mathworks.com/help/physmod/simscape/ug/modeling-moist-air-systems.html

Regards,

Joel

[omkar tulankar]

Hi joel ,

I am trying to define the gas dynamics using simscape gas systems .

Where I am trying to control the gas flow based on the temperature measured that is when set point temperature is reached , valve should open and vice versa.

For that I am using two valves , 1) Gate valve 2)Temperature control valve

Gate valve I am trying to control with the help of switch , if condition is true the valve will get a maximum lift intruction '1'. otherwise the lift is set to minimum lift condition '0'.

In temperature control valve , I am defining the actuation temperature for opening and closing of valve.

I am using constant volume chamber and constant temperature source(thermal) to elevate the temperature of gas .

*I am facing problem in controlling the flow , I am using constant volume source to maintain the flow but the flow control is not happening with opening and closing of valves.

I am attaching model for reference .

Can you please help me out in this.

Thanks in advance

[Joel Van Sickel]

Hello Omkar,

a few notes. Its very important to have realistic values for all the components in your model. I highly recommend starting simple, with as few blocks as possible, so delete your controlled valve and check valve and try to get that system working. Also, I would not use a flow rate source directly into a valve. Consider using a pressure source instead.

Regards,

Joel

[omkar tulankar]

Hi joel ,

As per your suggestions I tried changing the dimension of the valve according to real world dimensions and and simulate model . Following error I am getting while working on it .

[omkar tulankar]

Hi Joel,

Gate valve working is established, I am facing problem with temperature control valve .

That is when temperature control valve is closed above actuation temperature , it is also affefcting the volumetric flow rate at the gate valve end (though it is open ).

I have also tried to put check valve in between the network .

It is not helping out .

I want that when the temperature control valve closes , the vometric flow after the temperature control valve should be zero , while volumetric flow before the temperature control valve should remain constant .

Can you help me out in this ?

I am attaching my model for your reference.

Thanks in advance .

Waiting for you response .

[Joel Van Sickel]

Hello Omkar,

this is not physically possible. If a valve shuts off, the flow before and after it both go to zero. You would need a second pipe to divert the flow. The model is working correctly. If you have a single pipe, and any valve on it shuts, the flow in the whole pipe stops.

Regards,

Joel